Evidence-based management of peripheral vascular disease

Device-measured physical activity behaviours, and physical function, in people with type 2 diabetes mellitus and peripheral artery disease: A cross-sectional study

AIM

To quantify differences in device-measured physical activity (PA) behaviours, and physical function (PF), in people with type 2 diabetes mellitus (T2DM) with and without peripheral artery disease (PAD).

MATERIALS AND METHODS

Participants from the Chronotype of Patients with T2DM and Effect on Glycaemic Control cross-sectional study wore accelerometers on their non-dominant wrist for up to 8-days to quantify: volume and intensity distribution of PA, time spent inactive, time in light PA, moderate-to-vigorous PA in at least 1-minute bouts (MVPA1min), and the average intensity achieved during the most active continuous 2, 5, 10, 30, and 60-minute periods of the 24-h day. PF was assessed using the short physical performance battery (SPPB), the Duke Activity Status Index (DASI), sit-to-stand repetitions in 60 s (STS-60); hand-grip strength was also assessed. Differences between subjects with and without PAD were estimated using regressions adjusted for possible confounders.

RESULTS

736 participants with T2DM (without diabetic foot ulcers) were included in the analysis, 689 had no PAD. People with T2DM and PAD undertake less PA (MVPA1min: -9.2 min [95 % CI: -15.3 to -3.0; p = 0.004]) (light intensity PA: -18.7 min [-36.4 to -1.0; p = 0.039]), spend more time inactive (49.2 min [12.1 to 86.2; p = 0.009]), and have reduced PF (SPPB score: -1.6 [-2.5 to -0.8; p = 0.001]) (DASI score: -14.8 [-19.8 to -9.8; p = 0.001]) (STS-60 repetitions: -7.1 [-10.5 to -3.8; p = 0.001]) compared to people without; some differences in PA were attenuated by confounders. Reduced intensity of activity for the most active continuous 2-30 min in the 24-h day, and reduced PF, persisted after accounting for confounders. There were no significant differences in hand-grip strength.

CONCLUSIONS

Findings from this cross-sectional study suggest that, the presence of PAD in T2DM may have been associated with lower PA levels and PF.

Long-term effects of cilostazol on the prevention of macrovascular disease in patients with type 2 diabetes mellitus

We analyzed the medical records of 884 type 2 DM patients who were taking different antiplatelet agents for more than 2 years. Based on the records, occurrences of cardiovascular events for 10 years were evaluated. The composite disease-free survival rate for cilostazol monotherapy group was similar to aspirin subgroup (p=0.133).

Treatment with Pharmacological Agents in Peripheral Arterial Disease Patients Does Not Result in Biomechanical Gait Changes

Pharmacological treatment has been used to alleviate the claudication symptoms and improve walking performance in peripheral arterial disease (PAD) patients. However, the effects of claudication treatments on gait mechanics have not been objectively indentified with biomechanical techniques. For this study, 20 PAD patients were assigned to take either pentoxifylline (n= 11) or cilostazol (n= 9), the two FDA-approved pharmacological therapies used to treat intermittent claudication symptoms. All patients completed a gait evaluation protocol that involved the acquisition of kinematic and kinetic gait data before use of the medication and after 12 weeks of treatment. Results showed that treatment with either pentoxifylline or cilostazol resulted in limited overall improvement in gait parameters including joint angles and joint moments. Walking speed was unchanged, in either treatment group, as a result of the medication. These results suggest that to improve biomechanical walking parameters of PAD patients, clinicians cannot rely on drug therapies alone.

Dethrombosis of the lower extremity arteries using the power-pulse spray technique in patients with recent onset thrombotic occlusions: results of the DETHROMBOSIS Registry

PURPOSE

To assess the presence of thrombus using intravascular ultrasound (IVUS) and evaluate the feasibility of combined thrombolysis [power-pulse spray (P-PS)] and rheolytic thrombectomy (RT) in patients with recent-onset limb ischemia (<6 months) due to total occlusion of at least 1 infrainguinal vessel.

METHODS

Seventeen patients (12 women; mean age 68.3+/-10.7 years) enrolled in a prospective registry underwent IVUS imaging at baseline, after treatment with P-PS using tissue plasminogen activator and RT (AngioJet), and prior to definitive treatment of the vessel. The primary safety endpoints were major bleeding, distal embolization, vascular access complications, and renal failure. Effectiveness outcomes were (1) procedural success with a residual stenosis <30%, (2) IVUS-documented resolution of the thrombus, and (3) the combined clinical endpoint of procedure-related death, stroke, unplanned amputation, and unplanned urgent revascularization of the treated limb.

RESULTS

At baseline, the majority of patients (16, 94.1%) had a definite thrombus identified by IVUS; in the remaining patient (6.3%), thrombus was likely to be present according to the IVUS scan. By angiography, 2 (11.8%) patients had a definite grade 3 thrombus and 5 (29.4%) patients had a grade 1 thrombus (modified TIMI scale) at baseline. IVUS data were available pre and post P-PS/RT in 16 (94.1%) patients. In 10 (62.5%), the thrombus was partially resolved; in 5 (31.25%), there was no apparent change. The thrombus appeared to have completely resolved in only 1 (6.3%) patient. Embolization occurred in 3 (17.6%) patients with no adverse clinical sequelae. The combined clinical endpoint was met in 1 (5.9%) of 17 patients. After final definitive treatment of the vessel, acute procedural success was 100%, with no angiographic filling defects seen.

CONCLUSION

Thrombus is present in most if not all patients with a recent history of limb ischemia who are found to have an occluded culprit vessel. The application of the P-PS/RT led to partial or complete thrombus resolution in about two thirds of the patients treated. The overall safety outcome was favorable, but large studies are needed to test the effectiveness of the P-PS/RT technique prior to routine use.

Increased vascular thromboxane generation impairs dilation of skeletal muscle arterioles of obese Zucker rats with reduced oxygen tension

This study determined if altered vascular prostacyclin (PGI(2)) and/or thromboxane A(2) (TxA(2)) production with reduced Po(2) contributes to impaired hypoxic dilation of skeletal muscle resistance arterioles of obese Zucker rats (OZRs) versus lean Zucker rats (LZRs). Mechanical responses were assessed in isolated gracilis muscle arterioles following reductions in Po(2) under control conditions and following pharmacological interventions inhibiting arachidonic acid metabolism and nitric oxide synthase and alleviating elevated vascular oxidant stress. The production of arachidonic acid metabolites was assessed using pooled arteries from OZRs and LZRs in response to reduced Po(2). Hypoxic dilation, endothelium-dependent in both strains, was attenuated in OZRs versus LZRs. Nitric oxide synthase inhibition had no significant impact on hypoxic dilation in either strain. Cyclooxygenase inhibition dramatically reduced hypoxic dilation in LZRs and abolished responses in OZRs. Treatment of arterioles from OZRs with polyethylene glycol-superoxide dismutase improved hypoxic dilation, and this improvement was entirely cyclooxygenase dependent. Vascular PGI(2) production with reduced Po(2) was similar between strains, although TxA(2) production was increased in OZRs, a difference that was attenuated by treatment of vessels from OZRs with polyethylene glycol-superoxide dismutase. Both blockade of PGH(2)/TxA(2) receptors and inhibition of thromboxane synthase increased hypoxic dilation in OZR arterioles. These results suggest that a contributing mechanism underlying impaired hypoxic dilation of skeletal muscle arterioles of OZRs may be an increased vascular production of TxA(2), which competes against the vasodilator influences of PGI(2). These results also suggest that the elevated vascular oxidant stress inherent in metabolic syndrome may contribute to the increased vascular TxA(2) production and may blunt vascular sensitivity to PGI(2).

Prevalence of Metabolic Syndrome in Patients With Clinically Advanced Peripheral Vascular Disease

The aim of this cross-sectional study was to determine the prevalence of metabolic syndrome (MetS) and its components among 100 patients with progressive peripheral arterial disease (PAD) referred for diagnostic angiography in preparation for a revascularization procedure. The prevalence of MetS was more than 95%. Diabetes mellitus was the most prevalent component followed by hypertension and low high-density lipoprotein. Almost half the patients aggregated in the highest metabolic score category. A direct relationship was identified between the number of MetS components and serum uric acid ( P = .001) and C-reactive protein ( P = .826), whereas an inverse relationship was seen between the clustering of components and androgen levels in men ( P < .001). For PAD, which could have a benign clinical course, early screening for MetS might identify those at greater risk of failing conservative therapy and progressing to a more aggressive atherosclerotic disease typically associated with high morbidity and mortality.

Prescribing Practice of General Practitioners in Northern Ireland for Peripheral Arterial Disease

Peripheral arterial disease is prevalent and reflects overall cardiovascular disease state. Best medical treatment is the cornerstone of management to reduce peripheral arterial disease symptoms and to minimize vascular morbidity and mortality. The aim of this study was to assess the prescription practice of general practitioners in Northern Ireland for patients with peripheral arterial disease. All general practitioners were from the Northern Ireland Professional Medical Directory, and a questionnaire was used to determine the prescribing patterns for peripheral arterial disease. In all, 468 general practitioners responded; 94% prescribed aspirin to nondiabetic patients, and 44.9% prescribed statin, with similar results for diabetic patients. Angiotensin-converting enzyme inhibitors, multivitamins, and β-blockers were not often prescribed. Statin was prescribed to patients with diabetic peripheral arterial disease at a lower cholesterol concentration. In all, 52% would consider statin and fibrate together. Budgetary consideration influenced 6%. Northern Ireland general practitioners are reluctant to prescribe medication that is effective in the secondary prevention of vascular morbidity and mortality in high-risk patients.

An autopsy case of internal jugular vein thrombophlebitis involving sepsis following blunt neck injury

We report an unusual case of delayed death due to sepsis following closed blunt injury to the neck. The victim was a 71-year-old male with a clinical history of hypertension, diabetes and gout. He was found dead about three weeks after being assaulted. He had not consulted a hospital after the assault. Forensic autopsy demonstrated a large liquefied subcutaneous hematoma on the right side of the neck, peri- and thrombophlebitis of the right internal jugular vein. Otherwise, there was no evidence of trauma. Histological examination showed dermal vesicles in the skin covering the hematoma, accompanied by marked inflammatory cell infiltration phagocytosing gram-positive streptococci, subcutaneous edema, panphlebitis with partially organized thrombi and bacterial colonies, pulmonary edema and multiple pulmonary microthrombi involving bacterial aggregates. Postmortem serum C-reactive protein and neopterin levels were markedly elevated. These findings suggest sepsis as the cause of death, induced by infected internal jugular vein thrombophlebitis following blunt neck injury involving impaired skin barrier.

Epidemiology, classification, and modifiable risk factors of peripheral arterial disease

Peripheral arterial disease (PAD) is part of a global vascular problem of diffuse atherosclerosis. PAD patients die mostly of cardiac and cerebrovascular-related events and much less frequently due to obstructive disease of the lower extremities. Aggressive risk factors modification is needed to reduce cardiac mortality in PAD patients. These include smoking cessation, reduction of blood pressure to current guidelines, aggressive low density lipoprotein lowering, losing weight, controlling diabetes and the use of oral antiplatelet drugs such as aspirin or clopidogrel. In addition to quitting smoking and exercise, cilostazol and statins have been shown to reduce claudication in patients with PAD. Patients with critical rest limb ischemia or severe progressive claudication need to be treated with revascularization to minimize the chance of limb loss, reduce symptoms, and improve quality of life.

Similar Success Rates with Bivalirudin and Unfractionated Heparin in Bare-Metal Stent Implantation

BACKGROUND

Unfractionated heparin (UFH) is the traditional agent utilized during percutaneous peripheral interventions (PPIs) despite its well-known limitations. Bivalirudin, a thrombin-specific anticoagulant, overcomes many of the limitations of UFH and has consistently demonstrated comparable efficacy with significantly fewer bleeding complications. The purpose of this study was to compare procedural success in patients undergoing bare-metal stent implantation for atherosclerotic blockage of the renal, iliac, and femoral arteries and receiving either bivalirudin (0.75 mg/kg bolus/1.75 mg/kg/hr infusion) or UFH (50-70 U/kg/hr bolus) as the primary anticoagulant.

METHODS

This study was an open-label, nonrandomized retrospective registry with the primary endpoint of procedural success. Secondary endpoints included incidence of: death, myocardial infarction (MI), urgent revascularization, amputation, and major and minor bleeding.

RESULTS

One hundred and five consecutive patients were enrolled (bivalirudin = 53; heparin = 52). Baseline demographics were comparable between groups. Patients were pretreated with clopidogrel (approx. 71%) and aspirin (approx. 79%). Procedural success was achieved in 97% and 96% of patients in the bivalirudin- and heparin-treated groups, respectively. Event rates were low and similar between groups.

CONCLUSION

Bivalirudin maintained an equal rate of procedural success in this cohort without sacrificing patient safety. Results of this study add to the growing body of evidence supporting the safety and efficacy of bivalirudin as a possible substitute for UFH in anticoagulation during peripheral vascular bare-metal stent implantation.

Drug/device combinations for local drug therapies and infection prophylaxis

Combination devices-those comprising drug releasing components together with functional prosthetic implants-represent a versatile, emerging clinical technology promising to provide functional improvements to implant devices in several classes. Landmark antimicrobial catheters and the drug-eluting stent have heralded the entrance, and significantly, routes to FDA approval, for these devices into clinical practice. This review describes recent strategies creating implantable combination devices. Most prominent are new combination devices representing current orthopedic and cardiovascular implants with new added capabilities from on-board or directly associated drug delivery systems are now under development. Wound coverings and implantable sensors will also benefit from this combination enhancement. Infection mitigation, a common problem with implantable devices, is a current primary focus. On-going progress in cell-based therapeutics, progenitor cell exploitation, growth factor delivery and advanced formulation strategies will provide a more general and versatile basis for advanced combination device strategies. These seek to improve tissue-device integration and functional tissue regeneration. Future combination devices might best be completely re-designed de novo to deliver multiple bioactive agents over several spatial and temporal scales to enhance prosthetic device function, instead of the current 'add-on' approach to existing implant device designs never originally intending to function in tandem with drug delivery systems.